As a tool holder having a hollow taper shank equipped with a main spindle of a machine tool, a tool holder having a shank specified in Deutsche Industrie Normen (DIN) 69893 (HSK shank), and a tool holder having a shank developed by Kennametal Inc. (KM shank) are known.
Various kinds of means, which identify the type or model number of a tool equipped with a spindle of a machine tool, have been proposed. For example, FIG. 2 of U.S. Pat. No. 3,704,510 discloses a tool holder having a coded collar. In this case, a binary code is read by using a switch mechanism based on a combination of a groove and a ring formed in the collar.
Japanese Unexamined Patent Publication (Kokai) No. 59-47134 discloses a tool holder having an identification mark formed by etching. The identification mark of the tool holder is read by a portable reader.
In addition to reading data of a tool, a means capable of writing data regarding used hours or an amount of offset of the tool has been used, in view of management of the dimension or life of the tool. For example, FIGS. 7 and 8 of U.S. Pat. No. 4,742,470 disclose a tool adapter (or a tool holder) having a transponder attached to a drive key slot. In this case, a transceiver having a read/write head is fixed to a machine tool, and information stored in a memory of the transponder is read or new information is saved in the memory.
Further, Japanese Unexamined Utility Model Publication (Kokai) No. 5-93733 discloses a tool holder having an ID tag attached to a pull stud. The ID tag is positioned in a recess formed at a head of the pull stud of the tool holder.
In the tool holder having the coded collar as disclosed in U.S. Pat. No. 3,704,510, or the tool holder having the identification mark formed by etching as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 59-47134, it may be difficult to correctly read data when a chip or machining fluid becomes adhered to the collar or the mark.
In the tool holder having the drive key slot as disclosed in U.S. Pat. No. 4,742,470, the ID tag may be relatively easily attached by inserting the ID tag in the key slot. However, since the ID tag is exposed outside, a chip or machining fluid may become adhered to the ID tag, resulting in it being difficult to correctly read/write. Further, since the ID tag is attached to the outside of the tool holder, the rotational balance of the tool holder may be deteriorated.
In the tool holder having the ID tag attached to the head of the pull stud as disclosed in Japanese Unexamined Utility Model Publication (Kokai) No. 5-93733, the ID tag is located at a rear end of the tool holder. Therefore, when an operator handles the tool holder, a chip may become adhered to the ID tag, or the operator may accidently damage the ID tag.